Numerous control mechanism which comprise a release device which is to operate under the action of an order which is as weak as possible, and must be, as far as possible, insensitive to vibrations and to shocks, are known. In practice, known mechanisms require, because of various friction between the parts which constitute them, high-level release orders. This friction causes therefore poor sensitivity, poor regularity in performance; moreover, known mechanisms are sensitive to shocks due to the manipulating of the trip knob. This generally requires the "hardening" of the release device to make it insensitive to these shocks and this gives rise, of course, to a loss of sensitivity of the release device.
The present invention is intended to obviate the disadvantages of known mechanisms and to obtain a sensitive mechanism which is regular in operation and practically insensitive to the shocks and vibrations compatible with the normal use of the mechanism.